As crosslinking treatment of a fluororubber, a method of peroxide-crosslinking a fluororubber by mixing it with an organic peroxide and heating the mixture, or a method of radiation-crosslinking a fluororubber by irradiating it with radioactive rays, as disclosed in the following Patent Document 1, have been known. At that time, in order to improve the crosslinking property of a fluororubber or the properties of a crosslinked rubber article obtainable, heretofore, a polyfunctional compound has been blended as a crosslinking coagent.
As the polyfunctional compound, triallyl isocyanurate has been preferably used (See Non-Patent Document 1 and Patent Document 1). By using triallyl isocyanurate as a crosslinking coagent, it is possible to improve a crosslinking rate of a fluororubber. Further, a triazine ring structure excellent in the heat resistance is inserted into a crosslinking site of a fluororubber, and therefore it is advantageous in that a crosslinked rubber article excellent in the heat resistance or mechanical properties is obtainable.